public HeaderDropDownList DropDownList {get; set;}

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Collections.Generic;

namespace GrapeCity.Win.MultiRow.SampleCode
{
    public class HeaderDropDownListDemo : Form
    {
        private GcMultiRow gcMultiRow1 = new GcMultiRow();
        private FlowLayoutPanel panel = new FlowLayoutPanel();

        public HeaderDropDownListDemo()
        {
            this.Text = "HeaderDropDownList Demo";
            this.Size = new Size(630, 350);

            // Initial flow layout panel and add to form.
            this.panel.Dock = DockStyle.Left;
            this.panel.Size = new Size(250, 200);
            this.panel.FlowDirection = FlowDirection.TopDown;
            this.panel.WrapContents = false;
            this.panel.Padding = new Padding(5);
            this.Controls.Add(panel);

            // Add MultiRow to form
            this.gcMultiRow1.Dock = DockStyle.Left;
            this.gcMultiRow1.Width = 380;
            this.Controls.Add(this.gcMultiRow1);

            this.Load += new EventHandler(Form1_Load);

            InitButton();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // Create a template with 4 text box cell.
            gcMultiRow1.Template = Template.CreateGridTemplate(4);

            gcMultiRow1.RowCount = 100;

            // Fill values.
            for (int rowIndex = 0; rowIndex < gcMultiRow1.RowCount - 1; rowIndex++)
            {
                for (int cellIndex = 0; cellIndex < 4; cellIndex++)
                {
                    gcMultiRow1[rowIndex, cellIndex].Value = rowIndex * 10 + cellIndex;
                }
            }
        }

        #region Button Event Handlers

        void setFirstColumnDropDownListButton_Click(object sender, EventArgs e)
        {
            // Get first column header cell.
            ColumnHeaderCell columnHeaderCell = this.gcMultiRow1.ColumnHeaders[0][0] as ColumnHeaderCell;

            // Create a drop down list with some default down down items.
            columnHeaderCell.DropDownList = new HeaderDropDownList(0, true, true);
        }

        void setSecondColumnDropDownListButton_Click(object sender, EventArgs e)
        {
            // Create a header drop down list without default down down items.
            HeaderDropDownList headerDropDownList = new HeaderDropDownList();

            // If do not indicate which cell to be filtered, the cell which has same index with column header cell in row section will be filtered.
            headerDropDownList.CellName = "textBoxCell2";

            DropDownItemCollection dropDownItemCollection = headerDropDownList.Items;
            // Initialize drop down items manually.
            // Add sort item.
            dropDownItemCollection.Add(new DropDownSortItem(SortOrder.Ascending));
            dropDownItemCollection.Add(new DropDownSortItem(SortOrder.Descending));
            
            // Add a separator line.
            dropDownItemCollection.Add(new DropDownSeparatorItem());

            // Add show all, black and none black items.
            dropDownItemCollection.Add(new DropDownShowAllFilterItem());
            dropDownItemCollection.Add(new DropDownBlanksFilterItem());
            dropDownItemCollection.Add(new DropDownNonBlanksFilterItem());

            // Add auto filter items.
            dropDownItemCollection.Add(new DropDownAutoFilterItem());

            // Get second column header cell.
            ColumnHeaderCell columnHeaderCell = this.gcMultiRow1.ColumnHeaders[0][1] as ColumnHeaderCell;
            columnHeaderCell.DropDownList = headerDropDownList;
        }

        void setThirdColumnDropDownListButton_Click(object sender, EventArgs e)
        {
            // Create a header drop down list without default down down items.
            HeaderDropDownList headerDropDownList = new HeaderDropDownList();

            DropDownItemCollection dropDownItemCollection = headerDropDownList.Items;

            // Initialize drop down items manually.
            // Add show all item.
            dropDownItemCollection.Add(new DropDownShowAllFilterItem());

            DropDownAutoFilterItem autoFilterItem = new DropDownAutoFilterItem();

            autoFilterItem.DropDownItemNeeded += new EventHandler<DropDownItemNeededEventArgs>(autoFilterItem_DropDownItemNeeded);

            // custom range item.
            dropDownItemCollection.Add(autoFilterItem);

            // Get second column header cell.
            ColumnHeaderCell columnHeaderCell = this.gcMultiRow1.ColumnHeaders[0][2] as ColumnHeaderCell;
            columnHeaderCell.DropDownList = headerDropDownList;
        }

        void autoFilterItem_DropDownItemNeeded(object sender, DropDownItemNeededEventArgs e)
        {
            int filterValue = int.Parse(e.FilterValue.ToString());

            e.DropDownCustomFilterItem = new AutoRangeFilterItem(filterValue / 100);

            e.Handled = true;
        }

        public class AutoRangeFilterItem : DropDownCustomFilterItem
        {
            public AutoRangeFilterItem(int filterValue)
                : base(filterValue)
            {

            }

            public override string Text
            {
                get
                {
                    return ((int)FilterValue * 100).ToString() + " to " + (((int)FilterValue + 1) * 100).ToString();
                }
                set { }
            }

            protected override bool Check(object value)
            {
                // check the value whether in specific range.
                int checkedValue = int.Parse(value.ToString());

                return (checkedValue >= ((int)FilterValue * 100) && checkedValue <= (((int)FilterValue + 1) * 100));
            }
        }

        void setFourthColumnDropDownListButton_Click(object sender, EventArgs e)
        {
            // Create a header drop down list without default down down items.
            HeaderDropDownList headerDropDownList = new HeaderDropDownList();

            DropDownItemCollection dropDownItemCollection = headerDropDownList.Items;

            // Initialize drop down items manually.
            // Add show all item.
            dropDownItemCollection.Add(new DropDownShowAllFilterItem());

            // custom range item.
            dropDownItemCollection.Add(new PopupFilterItem());

            // Get second column header cell.
            ColumnHeaderCell columnHeaderCell = this.gcMultiRow1.ColumnHeaders[0][3] as ColumnHeaderCell;
            columnHeaderCell.DropDownList = headerDropDownList;
        }

        public class PopupFilterItem : DropDownCustomFilterItem
        {
            public override string Text
            {
                get
                {
                    if (this.Checked)
                    {
                        return min.ToString() + " to " + max.ToString();
                    }
                    return "(Custom)";
                }
                set { }
            }

            int max = -1;
            int min = -1;

            protected override bool Check(object value)
            {
                // check the value whether in specific range.
                int checkedValue = int.Parse(value.ToString());

                return (checkedValue >= min && checkedValue <= max);
            }

            protected override void OnClick(EventArgs e)
            {
                // Initialize pop up form.
                Form form = new Form();

                FlowLayoutPanel panel = new FlowLayoutPanel();
                panel.Height = form.Height;

                Label label1 = new Label();
                label1.Text = "Min Value:";

                Label label2 = new Label();
                label2.Text = "MaxValue:";

                NumericUpDown numericUpDown1 = new NumericUpDown();

                NumericUpDown numericUpDown2 = new NumericUpDown();
                numericUpDown2.Maximum = 1000;
                numericUpDown2.Value = 50;

                Button okButton = new Button();
                okButton.Text = "OK";
                okButton.DialogResult = DialogResult.OK;
                form.AcceptButton = okButton;

                form.Controls.Add(panel);
                panel.Controls.Add(label1);
                panel.Controls.Add(numericUpDown1);
                panel.Controls.Add(label2);
                panel.Controls.Add(numericUpDown2);
                panel.Controls.Add(okButton);

                DialogResult result = form.ShowDialog();

                // If input a range and click OK button. Update range.
                if (result == DialogResult.OK)
                {
                    min = (int)(numericUpDown1.Value);
                    max = (int)(numericUpDown2.Value);
                }
                else
                {
                    min = int.MinValue;
                    max = int.MaxValue;
                }

                base.OnClick(e);
            }
        }

        #endregion

        #region Initialize Buttons

        private void InitButton()
        {
            AddButton(setFirstColumnDropDownListButton, "Set 1st column drop down list", new EventHandler(setFirstColumnDropDownListButton_Click));
            AddButton(setSecondColumnDropDownListButton, "Set 2nd column drop down list", new EventHandler(setSecondColumnDropDownListButton_Click));
            AddButton(setThirdColumnDropDownListButton, "Set 3rd column custom drop down list", new EventHandler(setThirdColumnDropDownListButton_Click));
            AddButton(setFourthColumnDropDownListButton, "Set 4th column custom drop down list", new EventHandler(setFourthColumnDropDownListButton_Click));
        }

        private void AddButton(Button button, string text, EventHandler eventHandler)
        {
            this.panel.Controls.Add(button);
            button.Text = text;
            button.AutoSize = true;
            button.Click += eventHandler;
        }

        Button setFirstColumnDropDownListButton = new Button();
        Button setSecondColumnDropDownListButton = new Button();
        Button setThirdColumnDropDownListButton = new Button();
        Button setFourthColumnDropDownListButton = new Button();

        #endregion

        [STAThreadAttribute()]
        public static void Main()
        {
            Application.EnableVisualStyles();
            Application.Run(new HeaderDropDownListDemo());
        }
    }
}